What is Form W-9?

Form W-9 is the way that a taxpayer provides his taxpayer identification number to a party who must file that information with the IRS for purposes that include real estate transactions and cancellation of debt, according to the IRS. Taxpayers also fill out their mailing address on the form.

Employers use Form W-9 to help with payroll but do not submit the form to the IRS, says TurboTax. Instead, employers use the W-9s to assist with paychecks and W-2s. A person who conducts freelance or contract work occasionally needs to submit a W-9 to a client who requests one so that the client is able to report the payments made.